In a traditional design, a motor vehicle pedal, such as a brake pedal, is designed as a lever pivotably mounted around a substantially horizontal shaft, fixed relative to the structure of the vehicle.
More recently, to satisfy the standards and other safety stipulations in case of impact, in particular frontal impact, suffered by a motor vehicle, pedals have appeared provided with a special mounting allowing, following an impact, a certain release of the pedal intended to prevent that pedal from causing injuries to the legs or feet of the concerned vehicle's driver. The solutions proposed to that end in general consist of releasing the pivoting shaft of the pedal, either by sectioning the ends of said pivoting shaft, or more simply by allowing said pivoting shaft to move over a certain travel, along suitably oriented guiding slots or slits.
The latter solution is illustrated for example by German patent documents DE 4 409 324 A1 and DE 100 22 813 A1, or by French patent application FR 2 832 969 A1.
Considering more particularly the embodiment disclosed by document FR 2 832 969 A1, a pedal that is in particular a brake pedal is pivotably mounted along an axis of rotation on a bracket, provided with two parallel plates. A driving lever, which can be connected to a fixed portion of the vehicle, imposes, in case of impact, a movement of the pivoting shaft relative to the bracket, in a direction defined by parallel slots formed in the two plates of the bracket. Thus, in case of frontal impact, the pivoting shaft of the pedal is moved from a first position, which is its normal position, toward a second position situated further back (relative to the front-to-back direction of the vehicle), the backward movement of the shaft occurring along the path imposed by the slots. This backward movement of the shaft in turn requires tilting of the pedal assembly, so that the shoe thereof is moved forward relative to its normal position. The purpose of this operating mode is to avoid risks of lesions, in particular at the driver's ankles, these risks being caused by the penetration of the shoe inside the passenger compartment as a result of the deformation of the vehicle body.
In such an embodiment, the “release” of the pedal is partial, since the pivoting shaft thereof remains, even after an impact, engaged in the slots of the plates of the bracket. Furthermore, the movement freedom of the pivoting shaft depends on the gripping of the ends of said shaft on both plates. The residual friction on these plates opposes the movement of the shaft, therefore of the pedal, resulting in the need to impose the travel path of this shaft through complete guiding in the slots and by the driving lever.